1. Field of the Invention
The present invention relates in general to a method and apparatus for tracking distorted signals through a digital system. More particularly, the present invention relates to a method and apparatus for identifying distorted output signals from a digital filter caused by a distorted input signal to the digital filter.
2. Introduction
A distorted signal in a digital system may result because a digital component in the digital system operated beyond its dynamic range due to a multiplication or summation operation in the digital system, for example. Analog-to-digital conversion and digital filtering are common signal processing algorithms performed in a digital system that cause distorted signals in a digital system may result from distorted input signals to the digital system. For example, in digital filters, a single distorted input signal may create a stream of distorted output signals. This occurs because of the widening characteristics of a digital filter due to non-zero filter coefficients of the digital filter. In addition, the effect of a distorted input signal on output signals of a digital filter may be delayed due to the pipelined implementation of the digital filter. That is, if a distorted input signal is input to the digital filter at time t1, then the distorted input signal may cause a distorted output signal from the digital filter at time t2, where t2>t1.
Distorted signals may reduce the accuracy of the digital system and generate erroneous data. For example, if a distorted signal in a digital system is used to compute filter weights for a digital filter, the accuracy of the digital system may be reduced. Therefore, it is desirable to track the distorted signals so that their deleterious effects may be reduced by, for example, excluding the distorted signal.
However, conventional tracking devices only identify distorted signals that result from distorted input signals. Accordingly, there is a need for tracking device for identifying distorted signals resulting from distorted input signals.